(define (equal? a b)
    (cond 
        ((and (not (pair? a)) (not (pair? b))) 
            (eq? a b)
        )        
        ((and (pair? a) (pair? b)) 
            (and 
                (equal? (car a) (car b))
                (equal? (cdr a) (cdr b))
            )
        )
        (else #f)
    )
)
(display (equal? `(this is a list) `(this is a list)))
(newline)
(exit)